The defense of necessity may apply when an individual commits a criminal act during an emergency situation in order to prevent a greater harm from happening. In such circumstances, our legal system typically excuses the individual’s criminal act because it was justified, or finds that no criminal act has occurred. Although necessity may seem like a defense that would be commonly invoked by defendants seeking to avoid criminal charges, its application is limited by several important requirements:
The defendant must reasonably have believed that there was an actual and specific threat that required immediate action
The defendant must have had no realistic alternative to completing the criminal act
The harm caused by the criminal act must not be greater than the harm avoided
The defendant did not himself contribute to or cause the threat
Only if all of these requirements are met, will the defense of necessity be applicable. It is also important to note that in some jurisdictions, necessity is never a defense to the killing of another individual, no matter what threat they may present.
Under the defense of necessity, an individual must reasonably believe, first and foremost, that there is an imminent and actual threat that requires immediate action. Thus, for instance, a school bus driver may be driving a bus of school-aged children when he loses control of his brakes as he is approaching a steep turn on a mountain road. He is faced with an actual and immediate threat that the bus may go out of control and drive off the road, risking the lives of countless children on the bus.
Like other crimes, most states require that this threat would be reasonably apparent to the average individual and is not a threat that the defendant experienced only subjectively. Here, a reasonable person would certainly agree that an out of control bus with children on it is an actual threat to safety.
No Realistic Alternative
Because the defense of necessity is essentially a justification for the criminal act, it is imperative that the defendant had no other realistic options available to him at the time the criminal act was committed. If he did, his criminal actions would not be justified. This does not mean, however, that no alternative whatsoever must exist. Generally, the individual will always have the option to simply let the greater harm occur and refrain from acting criminally, but courts have determined that this is not a “realistic” option.
In the example, for instance, if the bus driver had access to an emergency braking device that was designed to stop the bus when the regular brakes failed, he would not be justified in committing a criminal act to prevent collision because he had a realistic alternative available to him.
No Greater Harm
When an individual is evaluating whether it is necessary to undertake a criminal act in order to avoid a more serious problem from arising or occurring, the individual must be certain that no greater harm will arise from his or her criminal act than from the situation that would be avoided.
For instance, if, in order to avoid driving off the mountain road and plunging down the steep incline, the bus driver elects to drive the bus into a barn in order to stop the bus, he must be certain that no greater harm will come from this choice. Because it is a barn and perhaps appears empty to him, his criminal act of destroying the barn and any property inside will likely be considered less harmful than the lives lost if the bus careens over the road. However, if the bus drivers only alternative was to drive the bus into an area crowded with other people, he might, in fact, cause more harm through this alternative than would be prevented.
No Involvement in the Threat
Finally, any defendant claiming the defense of necessity cannot have contributed to or caused the threat that they were later seeking to avoid by committing the criminal act. Thus, if the bus driver had been advised by his mechanic that the brakes on his bus were failing, but decided not to have them replaced, he could have difficulty claiming the defense of necessity because his failure to act responsibly contributed to the threat he faced.